1. Field of the Invention
The present invention relates to an air spring in which a tubular flexible member is interposed between an upper face plate and a lower face plate.
2. Description of the Related Art
A conventional air spring that is frequently used for a railway vehicle or the like includes an upper face plate that is attached to the body of the vehicle, a lower face plate that is disposed on a wheel side below the upper face plate, a tubular flexible member that is interposed between the upper face plate and the lower face plate, and an elastic mechanism (stopper) that is interposed between the lower face plate and a support frame on the wheel side. A rubber bellows or the like is used as the tubular flexible member.
Although a puncture occurs in the above described air spring in some cases, that is, the air inside the flexible member escapes (the flexible member deflates), even in such cases there is a need to ensure safe running of the vehicle. Examples of an air spring that can ensure safe running of a vehicle at a time of deflation include, for example, as disclosed in Japanese Patent Application Laid-Open No. 2009-222197, an air spring in which a stopper rubber is provided between its upper face plate and its movable plate that is capable of changing position so as to approach or move away from the upper face plate.
An annular bead receiving section that has a cross-sectional convex shape is formed in a lower face plate of the aforementioned air spring. A lower end (bead section) of a bellows is fitted to an outer circumferential side of the bead receiving section. The air spring is configured so that, at a time of deflation, the movable plate sits in an area that is enclosed by the bead receiving section of the lower face plate.